Devices for dispensing predetermined quantities of a pressurized liquid are described in U.S. Pat. Nos. 3,104,785 and 4,892,232. For some applications, such as in the administration of insulin, it would be desirable to permit adjustment of the dose which is dispensed upon each actuation of the dispenser.
Recently it has been found that insulin can be advantageously administered in the form of a spray applied to the nasal tissues of the patient. Since the prescribed doses of insulin vary over a relatively wide range, it is not possible to use any single unit dispenser for all patients unless each actuation of the dispenser emits only a very small quantity of insulin constituting a small percentage of a prescribed dose, thereby necessitating repeated operation of the dispenser for each prescribed dose of insulin. This multiple operation of the dispenser for each dose requires that the patient accurately count the number of times the dispenser is actuated to insure that the prescribed dose is administered. This procedure is not only unecessarily time consuming, but it can result in the improper administration of medication to the patient.
Therefor, it would be desirable to provide a dispenser which emits an adjustable, but precise, dose of insulin or other liquid upon each actuation of the dispenser. Preferably, the adjustment should be made without the use of special tools or the like so as to permit the physician as well as the patient to easily adjust the dose to be dispensed upon each actuation of the dispenser.